Manufacturing process of a hybrid solar panel

ABSTRACT

The invention relates to a hybrid solar panel comprising: photovoltaic elements having a front face and a rear face; a heat exchanger arranged opposite the rear face of said photovoltaic elements; and a cooling fluid circulating in said exchanger in such a way as to cool the photovoltaic elements, said exchanger comprising a heat exchange region through which said fluid flows, arranged beneath said photovoltaic elements, said exchange region comprising elements that enable the flow of the fluid to be disrupted in such a way as to stimulate the heat exchanges in the exchange region. The invention is characterised in that said exchange region is formed by a lower exchange plate designed in such a way as to form built-in obstruction elements extending over the entire thickness of the strand of cooling fluid flowing through the exchange region, and in that the upper end of the obstruction elements is in contact with the rear face of the photovoltaic elements in such a way that said photovoltaic elements are cooled mainly at these contact points.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/988,758, filed Sep. 13, 2013, which is a National PhaseApplication of PCT International Application No. PCT/FR2011/052718,entitled “HYBRID SOLAR PANEL”, International Filing date Nov. 21, 2011,published on May 31, 2012 as International Publication No. WO2012/069750, which in turn claims priority from French PatentApplication No. 1059597, filed Nov. 22, 2010, all of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD OF THE INVENTION

An object of the invention is a hybrid solar panel. The invention alsorelates to a method for cooling the photovoltaic elements of a hybridsolar panel as well as a method of manufacturing such a solar panel.

It relates to the technical field of heat exchangers for thermal controlof hybrid solar panels (capable of generating electrical energy andthermal energy), the aforementioned exchangers comprising means fordisrupting the flow of the coolant fluid.

PRIOR ART

Photovoltaic solar panels enable generation of electrical energy fromsolar rays. They comprise a plurality of photovoltaic elements(typically cells or thin layers), which operate according to theprinciple of the photoelectric effect. Generally, multiple photovoltaicelements are connected interspaced on a photovoltaic solar panel, andmultiple panels are assembled to form a solar plant. This plantgenerates electricity that can be consumed on site or to supply adistribution network.

Photovoltaic solar panels convert only a small part of the solarradiation into electricity (today less than 20%), the remainder beingunused heat. This heat is detrimental to the electrical performance ofsolar panels, as a decrease in the efficiency of photovoltaic elementswith temperature of approximately −0.45%/° C. can be observed. This iswhy it is doubly advantageous to cool the solar panels. Indeed, not onlydoes the efficiency of photovoltaic elements increase, but the heat fromthe cooling can be used in more or less complex heating systems. Wespeak then of hybrid solar panels capable of generating electrical andthermal energy.

Generally, a heat exchanger is positioned opposed to the rear face ofthe photovoltaic elements as so to cool the latter. The followingpatents describe a certain number of heat exchangers for solar panels:FR 2,319,585 (LIEBARD); FR 2,566,183 (LUCCIONI); FR 2,727,790(CYTHELIA); U.S. Pat. No. 4,361,717 (GILMORE); U.S. Pat. No. 4,184,543(KLEINE); U.S. Pat. No. 7,076,965 (LASICH); DE 197.47.325 (SCHRENK) orDE 10.2004.002.900 (MASCHKE).

All these exchangers enable cooling of the photovoltaic elements inorder to increase their performance. However, they have a number ofdrawbacks: their design can be relatively complex and makes the panelsheavy. They do not enable uniformly cooling the photovoltaic elements.The heat is not extracted in an optimized manner. It is necessary to usemuch energy in order to circulate the refrigerant, etc.

Known more particularly, from the document FR 2,911,997 (DIEMUNSCH), isa hybrid solar panel in which the heat exchanger comprises a lower platepositioned under the photovoltaic elements and on which flows a coolantfluid, with a laminar flow pattern. Elements for disrupting the flow ofthe coolant fluid are positioned on the base plate so as to so aspromote heat transfers. The disruption elements can be ribs oriented inthe direction of flow, the cylindrical or spherical obstacles enablingthe creation of three-dimensional Von Karman type vortexes, fins whoseheight is less than the thickness of the flow in order to createvortexes from edges of blades or impellers introduced into the thinvolume of into fluid, perpendicularly to the flow.

These different disruption elements are all assembled on the base plate.It is therefore necessary to attach them by gluing, welding or screwing,steps that complicate the design and that are time consuming. Costs formanufacturing such a heat exchanger industrially, that is to say inlarge quantities, are therefore relatively high.

Given this state of affairs, the main objective of the invention is tosimplify the design of heat exchangers for hybrid solar panels, so thatthey can be manufactured industrially, faster and at lower costs.

Among other objectives, to be achieved by the invention, can be cited: auniformity of temperature in the photovoltaic elements, an optimumextraction of heat, robustness of the solar panel while reducing itsweight.

DISCLOSURE OF THE INVENTION

The solution offered by the invention is a hybrid solar panelcomprising:

photovoltaic elements comprising a front face and a rear face,

a heat exchanger positioned opposed to the rear face of theaforementioned photovoltaic elements,

a coolant fluid circulating in the aforementioned heat exchanger so asto cool the aforementioned photovoltaic elements,

the aforementioned exchanger comprising a heat transfer zone positionedunder the aforementioned photovoltaic elements and wherein theaforementioned fluid flows, the aforementioned transfer zone comprisingelements enabling disruption of the flow of the aforementioned fluid soas to facilitate thermal transfers in the transfer zone.

This panel is remarkable:

in that the lower plate is formed so to form integrated disruptionelements extending over the entire thickness of the thin volume of theaforementioned coolant fluid flowing in the aforementioned transferzone. It therefore includes, after manufacturing, these disruptionelements, which greatly simplifies the manufacture of the exchanger,

and in that the upper end of the disruption elements is in contact withthe rear face of the photovoltaic elements so that the aforementionedphotovoltaic elements are mainly cooled at these contact points.

In an implementation variant, an upper exchange plate, advantageouslybased on aluminum, is attached to the rear face of the photovoltaicelements, the upper end of disruption elements being in contact with theaforementioned upper plate so that the temperature of the latter ishomogenous without cold or hot spots.

Whatever the solution, the technical result is the same. Indeed, thethermal contact between the disruption elements and the rear face of thephotovoltaic elements (or the upper exchange plate), provides aneffective heat transfer to the lower plate which is not possible withthe panel described in the document FR 2,911,997 cited above.

The lower plate can thus efficiently extract heat from the photovoltaicelements, which is evacuated by the coolant fluid. The latter thusrecuperates not only the heat at the back of the photovoltaic elements,but also at the lower plate.

The disruption elements preferably form bumps at the upper face of thelower plate on which the coolant fluid flows and form recesses at thelower face of the aforementioned plate that is not in contact with theaforementioned fluid and that is opposed to the aforementioned upperface.

The lower plate is advantageously metallic and stamped so as to form thedisruption elements.

Preferably, the heat exchanger is a monobloc piece, the lower platebeing shaped so as to constitute not only the transfer zone, but also aninlet zone and a discharge zone for the coolant fluid.

The lower plate can be shaped so as to constitute not only the heattransfer zone, but also all or part of the substrate upon which thephotovoltaic elements rest.

The heat exchanger preferentially comprises channels for circulating thecoolant fluid, positioned on both sides of the transfer zone, theaforementioned channels having pressure drops providing a uniformdistribution of the aforementioned fluid in the aforementioned transferzone. The lower plate can be shaped so as to form these distributionchannels.

In order to optimize the homogenization of the coolant fluid in thetransfer zone, the depth of the flow channels is preferably greater thanthe thickness of the thin volume of the aforementioned fluid flowing inthe aforementioned transfer zone. More generally, the pressure dropsgenerated in the circulation channels are negligible compared to thoseinduced in the transfer zone.

The rear face of the exchanger can be devoid of any thermal insulationmeans.

According to another feature of the invention, a long thin junction boxis positioned on the rear face of the aforementioned panel, preferablyagainst a rear edge of the aforementioned panel, and more generallywithout being opposed to the rear face of a photovoltaic element. Thisfeature is technically independent of other features described above andin particular the design of the exchanger.

Another aspect of the invention relates to a method for cooling thephotovoltaic elements of a hybrid solar panel, comprising:

circulating a coolant fluid in a heat transfer zone positioned under theaforementioned photovoltaic element so as to cool them,

disrupting the flow of the aforementioned fluid in the aforementionedtransfer zone,

This method is remarkable in that the coolant fluid is disrupted byincorporating, in the transfer zone, disruption elements, obtained bythe shaping of a lower exchange plate, the aforementioned elementsextending over the entire thickness of the thin volume of theaforementioned fluid flowing in the aforementioned transfer zone.

Yet another aspect of the invention relates to a method of manufacturinga hybrid solar panel in which a heat exchanger is positioned under thephotovoltaic elements of the aforementioned panel, the aforementionedmethod comprising:

positioning a lower exchange plate under the aforementioned photovoltaicelements, and on which is designed to flow a coolant fluid, theaforementioned plate forming a heat transfer zone comprising elementsenabling disruption of the flow of the aforementioned fluid,

shaping the aforementioned lower plate so as to form integrateddisruption elements adapted to extend over the entire thickness of thethin volume of the aforementioned coolant fluid flowing in theaforementioned transfer zone.

Preferably, a metal lower plate that is stamped to form the disruptionelements is used.

DESCRIPTION OF FIGURES

Other features and advantages of the invention will become betterapparent upon reading the description of a preferred implementation modethat will follow, with reference to the accompanying drawings, made byway of illustrative and non-limiting examples and in which:

FIG. 1 is a schematic sectional view of a hybrid solar panel inaccordance with the invention,

FIG. 2 is an enlarged view of the detail D1 of FIG. 1,

FIG. 3 is a schematic sectional view of a hybrid solar panel inaccordance with the invention, in an implementation variant,

FIG. 4 is an enlarged view of the detail D2 of FIG. 3,

FIG. 5 is a sectional view along A-A of the panel of FIG. 1, thedisruption elements being arranged linearly,

FIG. 6 shows the panel of FIG. 5 in an implementation variant, thedisruption elements being arranged staggered,

FIG. 7 shows, in perspective, a lower exchange plate in accordance withthe invention,

FIG. 8 is a top view of a solar panel fitted with an EDGE junction box,

FIG. 9 is a bottom view of the solar panel of FIG. 6,

FIGS. 10 a to 10 c schematically show different steps of manufacturingof a monobloc heat exchanger in accordance with the invention.

IMPLEMENTATION MODES OF THE INVENTION

The solar panel object of the invention is a hybrid panel; that is tosay it is able to generate electrical energy and thermal energy. It isdesigned to be used alone or in combination with other similar panels,so that the electrical and thermal energy it generates is usable by ahome or a plant.

Referring to FIGS. 1 to 4, the solar photovoltaic panel P includeselements 1 comprising a front face and a rear face. The front face isleft free so that it can receive solar radiation. The rear face isopposed to a heat exchanger E. The solar panel P comprises multiplephotovoltaic elements 1 connected in series or in parallel. The lattercan contain photovoltaic cells, photovoltaic thin films, etc. The typeof photovoltaic elements adapted to be used being well known to theperson of skill in the art, they will not be detailed here with morespecificity.

In practice, the photovoltaic elements 1 rest on the exchanger E whichacts as support. They can be attached directly on the latter, or befirst attached to a rigid frame that can itself be attached to theaforementioned exchanger. In case of presence of a frame, it is notnecessary, however, that there be attachment of the exchanger to thisframe. In fact, it is sufficient that the latter be placed under thephotovoltaic elements, without providing support function. In all cases,the exchanger E is positioned under the photovoltaic elements 1 so asnot to obstruct the solar rays.

A coolant fluid, which is typically glycol water, circulates in theexchanger E in order to recuperate the heat from the photovoltaicelements 1. In order to electrically protect the photovoltaic elements 1from the coolant fluid, a sealed electrical insulator 10 makes theinterface with the rear face of the aforementioned elements. There istherefore no direct contact between the electrical elements ofphotovoltaic elements 1 and the coolant fluid. This insulator 10 cancomprise a sheet (better known as the English term “back sheet”)pre-glued to the photovoltaic elements 1, or electrically insulatingadhesive (such as silicone gel for example). Within the meaning of thepresent invention, the “rear face” of the photovoltaic elements isunderstood to be electrically insulated by the electrically insulatingseal 10 and/or the upper plate 13 described later. The rear face ofphotovoltaic elements 1 is thus electrically insulated.

In practice, the heat exchanger E comprises three main zones: an inletzone ZA for the coolant fluid, a heat transfer zone ZE and a dischargezone ZV for the aforementioned fluid. The photovoltaic elements 1 arepreferentially assembled over the transfer zone ZE but can bedistributed over the inlet ZA and discharge ZV zones. The transfer zoneZE has for example a surface of between 0.5 m² and 4 m².

As shown in FIG. 7, the heat exchanger E is preferably a monobloc partobtained by stamping of a metal plate, by molding or otherwise. Theconfiguration of this monobloc part delimits not only the transfer zoneZE but also the inlet ZA and discharge ZV zones.

Referring to FIGS. 1-9, the inlet ZA and discharge ZV zones are formedby circulation channels 11, 12 positioned on each side of the transferzone ZE. These channels 11, 12 have the shape of gutters communicating,by their longitudinal edges, with the transfer zone ZE. They aremutually parallel and are oriented perpendicularly to the direction offluid flow in the heat transfer zone ZE. In FIGS. 5 to 6, the input eand the output s of the fluid in the heat exchanger E are primarilydiagonally opposed but can be arranged symmetrically at the same level.The input e and the output s can be located in the bottom of thecirculation channels 11, 12 or be made on the lateral walls of thelatter. The channels 11, 12, can have a rectangular, square,trapezoidal, round or other section, and have negligible pressure dropscompared to the pressure drops of the transfer zone ZE. In practice, thedepth of the circulation channels 11, 12 is greater than the thicknessof the thin volume of fluid flowing in the transfer zone ZE. This quasiabsence of pressure drops on the sides of the exchanger E acts as adistributor. Indeed, the fluid first fully fills the inlet channel 11before spreading uniformly in the transfer zone ZE. The fluid exits thelatter, and flows into the outlet channel 12, without encounteringobstacle. The occurrence of preferential paths for the coolant fluid areavoided, and hot spots are eliminated under the photovoltaic elements 1.

The heat transfer zone ZE is formed by a lower exchange plate 2positioned under the photovoltaic elements 1 and on which the coolantfluid flows. In accordance with the invention, the lower plate 2 isshaped so as to form disruption elements 20. The plate 2 thus includes,after manufacturing, these disruption elements 20 which are made of thesame material as the aforementioned plate. They have a double function:

to disrupt the flow of coolant fluid so as to promote the heat transferin the transfer zone ZE,

to increase the heat transfer surface and thus participate in the heattransfer.

In practice, the disruption elements 20 can have the form of ribs,nipples, semi-sphere, cylindrical or polygonal tubes, pyramids, etc.Along the surface of the transfer zone ZE, the number of disruptionelements 20 can vary from some dozen to several hundred. For example oneor several hundred disruption elements 20 per m² exchange surface can beprovided. For example 300 disruption elements per m² can be provided.They can be evenly distributed, and more specifically linearly, formingparallel flow paths, as shown in FIG. 5. In this case, the flow of thecoolant fluid is globally parallel, but locally disrupted at theelements 20. In an alternative implementation mode shown in FIG. 6, thedisruption elements 20 can be distributed irregularly, and particularstaggered. In this case, the flow of coolant fluid is disrupted withoutnecessarily being parallel.

The disruption elements 20 extend over the entire thickness of the thinvolume of fluid flowing in the transfer zone ZE. Referring moreparticularly to FIGS. 2 and 4, the height “h” of the disruption elements20 corresponds to the thickness of the thin volume of fluid flowing inthe transfer zone ZE. Thus, there is no thin volume of fluid that canpass over disruption elements 20. In practice, the thickness of the thinvolume of fluid in the transfer zone ZE (and height “h” of thedisruption elements 20) is a few millimeters.

A plate 2 is preferably made of aluminum or aluminum alloys, in order toobtain a good compromise between weight/price/thermal conductivity.However, other metals (copper, zinc, iron, . . . ) or other heatconductor materials (carbon, thermoplastics such as polyacetylene,polyaniline, polypyrrole; polymers filled with metal powders or flakes;. . . ) and suitable to a person of skill in the art can be used. Inpractice, a metal plate 2 that is pressed to form the disruptionelements 20 is used. Referring to FIGS. 1 to 4, it clearly appears thatthe disruption elements 20 form bumps at the upper face of the plate 2on which the coolant fluid flows and form recesses at the lower face ofthe aforementioned plate that is not in contact with the aforementionedfluid and that is opposed to the aforementioned upper face. Theserecesses increase the heat transfer surface between the plate 2 and theair circulating under the transfer zone ZE.

Referring to the implementation mode of FIGS. 1 and 2, the upper end ofthe disruption elements 20 is directly in contact with the rear face ofthe photovoltaic elements 1. The upper end of the disruption elements 20is for example glued to the insulator 10. The photovoltaic elements 1are mainly cooled at these contact points. The upper end of thedisruption elements 20 is shaped so as to provide a surface contact withthe rear face of the photovoltaic elements 1. This contact surface isadvantageously between 1 mm² and 10 cm², preferably approximately 3 mm²,more preferably approximately 4.5 mm². This surface contact, between theupper end of disruption elements and the rear face of the photovoltaicelement 1, provides an effective heat transfer to the lower plate 2. Thecoolant fluid thus recuperates the heat not only at the back of thephotovoltaic elements 1, but also at the lower plate 2, which greatlyincreases the heat transfer and optimizes the cooling of theaforementioned photovoltaic elements.

In an implementation variant shown in FIGS. 3 and 4, an upper exchangeplate 13 is attached to the rear face of the photovoltaic elements 1. Asfor the lower plate 2, an upper plate 13 is preferably made of aluminumor aluminum alloys. Other heat conductive materials described above andtype suitable to the person of skill in the art can, however, be used.

The upper end of the disruption elements 20 is shaped so as to provide asurface contact with the upper plate 13. This contact surface isadvantageously between 1 mm² and 10 cm², preferably approximately 3 mm²,more preferably approximately 4.5 mm². The upper plate 13 is for exampleglued or welded to the ends of the disruption elements 20 and/or on theedges of the exchanger E.

Multiple solutions enable assembly of the upper plate 13 and thephotovoltaic elements 1. The plate 13 can for example be glued on apre-glued insulating sheet on the rear face of the photovoltaic elements1. The plate 13 can also be attached on the rear face of thephotovoltaic elements 1 using an electrically insulating adhesive (forexample, silicone gel). It is also possible to coat the plate 13 with aninsulation film and to create a vacuum between the aforementioned plateand a glass/plastic stiffening plate, the photovoltaic elements beingplaced between the two aforementioned plates. The patch plate 13 ends uppressed to the glass/plastic plate by vacuum suction, the photovoltaicelements being sandwiched. In any event, regardless of the attachmenttechnique used, the plate 13 provides a sealing function for the coolantfluid.

The lower plate 2 tends to be colder than the upper plate 13, becausethe disruption elements 20 enable to cool it well. The upper end of thedisruption elements 20 provides a good thermal contact with the upperplate 13. This surface contact, between the upper end of the disruptionelements 20 and the upper plate 13, provides efficient transmission ofheat to the lower plate 2. The coolant fluid thus recuperates heat notonly at the upper plate 13, but also at the lower plate 2, which greatlyincreases the heat transfer and optimizes the cooling of theaforementioned photovoltaic elements. Because of its good thermalconductivity, the temperature of the upper plate 13 is homogenizedrapidly, the aforementioned plate being entirely cooled, withoutretaining cold or hot spots (while in the example of FIGS. 1 and 2, thecooling was occurring locally at the upper ends of the disruptionelements 20). The main advantage, of obtaining a uniform temperature onthe upper plate 13, is that the photovoltaic elements 1 will be cooleduniformly, thus no hot spot. The panel efficiency is thus increased,being recalled that the photovoltaic elements 1 set their electricitygeneration on the weakest element, that is to say, the hottest.

In accordance with the invention, the plate 2 is shaped so that itdirectly integrates the disruption elements 20. The plate 2 can also beshaped so as to constitute all or part of the substrate upon which thephotovoltaic elements 1 rest. Its bulkiness and weight being thusreduced, the exchanger E is nevertheless structurally superior withregard to the panel than exchangers known in the prior art. The plate 2can be also be shaped to form the distribution channels 11, 12 (FIG. 7).In this case, the exchanger E is monobloc, formed from a single piecedefining the inlet zone ZA of the coolant fluid, the heat transfer zoneZE with integrated disruption elements and the discharge zone ZV of theaforementioned fluid. One can, however, foresee attaching other piecesto the plate 2 in order to strengthen it. But in all cases, the numberof constituent parts of the exchanger E is reduced compared to theexchangers known from the prior art.

FIGS. 10 a to 10 c schematically show the different steps ofmanufacturing a monobloc exchanger incorporating not only the disruptionelements but also the lateral circulation channels. The illustratedtechnique is embossing (or die-stamping). A metal plate 2 is positionedopposing a die 201 and a punch 202 (FIG. 10 a). The die 201 and thepunch 202 have complementary indentations whose geometry corresponds tothe part to be made. Upon penetrating into the matrix 201, the punch 202will deform the plate 2 in order to shape it to the desired geometry(FIG. 10 b). It then suffices to separate the punch 202 from the matrix201 so as to obtain the exchanger E. The manufacturing method being verysimple and very rapid, this type of exchanger can be easilycommercialized.

It would also be possible to obtain a monobloc exchanger with othermanufacturing techniques such as casting, in the case where the materialused is of the type cast, filled polymers or thermoplastics.

Photovoltaic solar panels generally use junction boxes to house thebypass diodes. These boxes are generally rectangular in shape and areattached to the rear face of the panel. Given the bulkiness of theseboxes, the hybrid panels must fashion, by their geometry, theaforementioned boxes, by providing a housing in the exchanger. At thisjunction box housing, the heat transfer is disrupted, or diminished, sothat the photovoltaic elements located just above are not optimallycooled. This affects the output of the panel given that it is still thehottest photovoltaic element, thus the weakest, to which the panelassembly conforms.

To resolve this problem, long and thin junction boxes are used, forexample, such as EDGE boxes or TYCO® decentralized boxes. In practice,the box used has a length of approximately 130 mm, a width ofapproximately 12 mm and a height of approximately 12 mm. Referring toFIGS. 8 and 9, this junction box 4 is positioned on the rear face of thepanel P, preferably against a rear edge of the aforementioned panel, andmore generally without being opposed to the rear face of a photovoltaicelement 1. The thinness of such a box enables it to be completely“above” the first row of photovoltaic elements 1, the latter being thusall evenly cooled.

1. Manufacturing process of a hybrid solar panel capable of producing anelectric energy and a thermal energy, wherein a heat exchanger ispositioned opposed to a rear face of photovoltaic elements of the hybridsolar panel, comprising: molding a lower exchange plate and an upperexchange plate, each made out of a thermoplastic material, wherein thelower exchange plate forms a heat transfer zone, shaping the lowerexchange plate so as to form disruption elements enabling disruption ofthe flow of the fluid in the transfer zone, so as to facilitate thermaltransfers in the transfer zone, forming the disruption elements in theshape of nipples, semi-spheres, or pyramids, the disruption elementsforming bumps at an upper surface of the lower exchange plate andforming hollows at an underside of the lower exchange plate, assemblingthe upper exchange plate and the rear face of the photovoltaic elements,an upper end of the disruption elements being positioned in surfacecontact with the upper exchange plate, circulating a coolant fluid inthe heat exchanger, so that the coolant fluid recuperates heat from thephotovoltaic elements.
 2. Manufacturing process according to claim 1,comprising positioning the upper exchange plate on the rear face of thephotovoltaic elements, so as to form an electrically insulatingbacksheet of the photovoltaic elements.
 3. Manufacturing processaccording to claim 1, comprising using the rear face of the photovoltaicelements as the upper exchange plate.
 4. Manufacturing process accordingto claim 1, comprising shaping the lower exchange plate so as to form,several hundred disruption elements per m² of heat exchange surface, thedisruption elements being distributed in discontinuous staggered rows.5. Manufacturing process according to claim 1, comprising shaping thelower exchange plate so as to form the transfer zone and an inlet zoneand a discharge zone for the coolant fluid.
 6. Manufacturing processaccording to claim 1, comprising shaping the lower exchange plate so asto form the transfer zone and all or part of a substrate upon which thephotovoltaic elements rest.
 7. Manufacturing process according to claim1, comprising shaping the lower exchange plate so as to form channelsfor circulating the coolant fluid, positioned on both sides of thetransfer zone, the channels having pressure drops lower than a pressuredrop in the transfer zone providing a uniform distribution of the fluidin the transfer zone.
 8. Manufacturing process according to claim 1,comprising positioning a long thin junction box on the rear face of thehybrid solar panel, without being opposed to the rear face of aphotovoltaic element.